Field
Implementations described herein generally relate to methods and apparatus for in-situ removal of unwanted deposition buildup from one or more interior surfaces of a semiconductor substrate processing chamber.
Description of the Related Art
Currently, cobalt is a metal of choice for use in multilevel metallization processes that are crucial to device manufacturing, especially for the PMOS work function layers of metal-oxide-semiconductor field-effect transistor (MOSFET) as well as wetting layer for direct metal gap fill and complete gap fill. The multilevel interconnect features that drive the manufacturing processes have high aspect ratio apertures including contacts, vias, lines, gaps, and other features. Filling these features without creating voids or deforming the feature geometry is more difficult when the features have higher aspect ratios. Reliable formation of interconnects is also more difficult as manufacturers strive to increase circuit density and quality.
As the use of cobalt has permeated the marketplace due to a relative low cost and processing properties, manufacturers of semiconductor, solar, and other electronic devices continue to look for ways to increase conductivity while improving surface roughness of the cobalt layer and improving the boundary regions between cobalt and other material layers by reducing cobalt diffusion and agglomeration. Several processing methods including, for example, physical vapor deposition (PVD) and chemical vapor deposition (CVD), have been developed to manufacture interconnects containing cobalt as feature sizes have decreased.
Unwanted deposition of cobalt on the interior surfaces such as the walls and chamber parts of the ALD or CVD processing chambers may occur during cobalt deposition processes. Such unwanted cobalt deposition may create particles and flakes within the chamber, resulting in the drift of process conditions and more importantly affecting the process reproducibility and uniformity.
In order to achieve high chamber availability while reducing the cost of ownership for production and maintaining film quality, a chamber clean is required to remove cobalt residue from the interior surfaces of the processing chamber including the process kits, e.g., showerhead, etc. Unfortunately, most cobalt compounds are non-volatile which makes cobalt compounds very difficult to remove. Currently, cobalt is removed from processing chambers using ex-situ cleaning processes where production is stopped, the processing chamber is opened, and the chamber parts are removed for cleaning using wet-clean processes.
Therefore, a need exists for methods for removing unwanted cobalt deposition from substrate processing chambers.